Download GENETICS!!!

• GENETICS!!!
Genetics
Genetics is the study of the
transmission of biological
information from one
generation to the next.
Father of genetics is Mendel
•1. Genes are sections
of DNA which are
responsible for
making a particular
protein (a
polypeptide).
•2. Genes are located
on chromosomes.
Each chromosome
has thousands of
genes on it.
•3. Your genes
determine your
physical (an
mental)
characteristics.
•4. Humans have 23
pairs of chromosomes.
__ total.
•5. You get one set
from your mother and
one from your father.
•6. Each of the pairs
consists of 2
homologous
chromosomes. These
are similar in shape,
size, and genetic
make-up.
•7. This arrangement
gives you 2 genes
for a characteristic
on each
chromosome.
•8. Alleles are
alternate forms of
the same gene.
Usually one allele
will be dominant
while one will be
recessive.
• 9. The dominant allele is
represented by a capital
letter. The recessive by a
lower case letter.
• 10. A dominant allele will
mask a recessive allele.
•11. The kinds of genes
you have make up
your genotype. You
cannot see a person
genotype because the
recessive allele may
be masked.
•12. The phenotype
is the outward
expression of your
genetic make-up. It
can be seen.
• 13. Each gamete unites at
fertilization to form a
zygote.
• The male gamete is the
sperm.
• The female is the egg.
•14. Gametes are
called reproductive
or germ cells. The
others are called
somatic cells.
•15. Because each
gamete only has 23
chromosomes it is
said to be haploid.
The zygote is diploid
because it has a full
46 chromosomes.
Mitosis & Meiosis
• 1. Somatic (body) cells
undergo mitosis.
• 2. Reproductive cells
(egg and sperm) undergo
meiosis.
• 3. You make about 25
million cells per second.
• 4. Mitosis refers to nuclear
division.
• 5. Mitosis results in new
cells with DNA that is
identical to the original cell.
Mitosis occurs in organisms
undergoing growth,
development, repair, or
asexual reproduction.
• 6. Mitosis results in two
daughter cells with the
same genetic make-up as
the parent cell.
• 7. There are four phases of
mitosis.
• 1 – prophase
• 2 – metaphase
• 3 – anaphase
• 4 - telophase
• In prophase the cell gets
ready for separation of
nuclear material. The
chromosomes thicken and
shorten. Each chromosome
is made up of two strands
called chromatids.
• Each chromosome has a
structure called a
centromere to hold the
chromosomes together.
• The chromosomes begin to
move to an area halfway
between the two centrioles
along the equatorial plane.
The cell membrane begins
to disappear.
• In metaphase the
chromosomes complete the
move to the equatorial
plane. The centromeres
attach to microtubules at
the ends of the cell.
• Metaphase ends when the
centromeres divide and the
chromatids become
separate chromosomes.
• In anaphase the main
event is the separation and
movement of the two sets
of chromosomes to
opposite ends of the cell.
• Division of the cytoplasm
usually begins at the end of
anaphase.
• Telophase – the last stage
of mitosis. The
chromosomes are at
opposite ends of the cell.
New nuclear membranes
form around the
chromosomes.
• In animals cells a furrow
begins to form during
anaphase. It is an indention
that pinches the cell
membrane inward. During
telophase the furrow
deepens.
• The furrow deepens until
the cell is pinched in half
and two daughter cells are
formed.
• Mitosis is complete when
the daughter cells enter the
interphase stage.
•8. After mitosis,
cytokinesis begins.
This is when the
cytoplasm is divided in
½ and two individual
cells are formed.
•9. Each new
daughter cell is
genetically
identical and
diploid.
•11. Between cell
divisions the cell goes
through interphase.
• 12. During interphase the
cell grows, the DNA
replication occurs,
chromosomes begin to
condense, microtubules are
made, and organelles are
replicated.
• 13. The process by which a
copy of the DNA molecule is
produced is called
replication. Replication is
semi-conservative because
half of the old molecule is
conserved in each new
molecule.
MEIOSIS
• 1. Meiosis is a type of cell
division which produces four
reproductive cells.
• 2. These four cells are
haploid. They contain ½ the
number chromosomes as the
parent cell.
•3. Meiosis consists
of two cell divisions.
Meiosis I and
meiosis II.
• 4. In meiosis I the
homologous chromosomes
line up next to each other
and crossing over occurs.
This is an exchange of
segments.
• 5. The cell then splits into
two daughter cells each
with one pair of
homologous chromosomes.
• 6. In meiosis II the two
daughter cells divide again.
The result is four haploid
gametes with ½ the
number of chromosomes as
the parent cell.
• 7. When a male and female
gamete unite in fertilization
the 2 haploid gametes will
make up one diploid
zygote.
• 8. This allows for some of
each parents genetic traits
to be passed on to the
offspring.
• 9. The principle of
segregation states that
pairs of genes are
distributed between
gametes during gamete
formation.
• 2. Many diseases are
passed from parent to
child. These are said to be
inherited. A person may be
a carrier of the allele
causing the disease and not
know it.
• 3. This may occur if the
allele is recessive.
• 4. Some diseases are sexlinked meaning the allele
for the disease is carried on
the sex chromosome.
• 5. Examples of sex-linked
diseases are
–Muscular dystrophy
–hemophilia
DNA
• 1. There are two major
kinds of molecules that
direct the synthesis of
proteins in eukaryotic cells.
• 2. RNA and DNA.
• 3. The study of the
structure and function of
DNA and RNA is called
molecular genetics.
DNA
• 1. Deoxyribonucleic acid.
• 2. Shaped like a double
helix.
• 3. Contains the genetic
code for an organism.
• 4. Discovered by Watson
and Crick.
• 5. DNA consists of two long
strands attached by short
strands.
• 6. The long strands are
made of sugars
(deoxyribose) and
phosphates.
• 7. The short strands are
made of nitrogencontaining bases. There are
four bases.
• 8. Adenine and guanine
(purines)
• 9. Cytosine and thymine
(pyrimidines)
• 10. The adenine and thymine
always pair up together.
• 11. The guanine and cytosine
always pair up together.
• 12. This is called base pairing.
• 13. Mutations are mistakes
which occur in the
duplication of DNA.
• 14. There are two
classifications of mutations.
• 15. Gene mutations (point
mutations) are mistakes
that affect individual genes
on a chromosome. (sickle
cell)
• 16. Chromosomal
mutations are mistakes
that affect the whole
chromosome.
• 17. Down Syndrome is an
example of a chromosomal
mutation. Results from
three copies of
chromosome 21.
• 18. Only mutations that
occur in the reproductive
cells can be passed on to
the next generation.
Punnett Squares
• 1. These are used to
determine the outcome of
crosses between
individuals.
• Ex. Brown eyes dominant
over green.
B = brown
b = green
• Homozygous – each allele
the same. Ex. = BB & bb
• Heterozygous – each allele
is different. Ex. = Bb
1. HH –
2. Kk –
3. Mm –
4. rr –
5. Jj –
6. qq –
7. FF –